Simulation and Interpersonal Utility

Abstract

The aim of this article is to show how research in cognitive science is relevant to a certain theoretical issue in moral theory, namely, the legitimacy of interpersonal utility (IU) comparisons. The legitimacy of IU comparisons is important to ethics for at least two reasons. First, certain ethical theories rely essentially on IUjudgments, so the viability of those views rests on the tenability of such judgments. Repudiation of IU comparisons threatens not only utilitarianism but all approaches to social theory that invoke welfare comparisons across individuals. Second, skepticism about IU comparisons has led social choice theorists to adopt conceptual tools unsullied by such comparisons, but the normative adequacy of these tools is in doubt. I specifically have in mind here the concept of Pareto optimality, or Pareto efficiency. An allocation of goods is called Pareto efficient just in case there is no feasible alternative allocation where everyone would be at least as well off and at least one agent would be strictly better off. This definition invokes only interpersonal welfare comparisons. But the concept of Pareto efficiency is extremely weak as a normative concept. Pareto efficient states are a dime a dozen, and there is little temptation to regard every such state as normatively acceptable. (For example, an allocation where one agent gets everything in the economy and all others get nothing is Pareto efficient, since any reallocation would make the first agent worse off.) It is therefore essential to review the question of whether principled avoidance of IU comparisons is indeed required. As Amartya Sen points out, different moral theories may require different types of IU comparisons.' Classical utilitarianism, for example, requires the maximization of a welfare sum, and therefore needs comparisons of welfare differences across individuals. On a Rawlsian